This invention relates to a novel synthetic diamond article that combines the desirable characteristics of other diamond products, both synthetic and natural. More specifically, this novel diamond article exhibits the optical, mechanical and thermal properties of a gem diamond, while maintaining the high growth rates of chemically vapor deposited diamonds. This invention further relates to a novel method of producing a synthetic diamond article.
Synthetic diamond products of the prior an take many forms: mesh, sintered polycrystalline compacts, chemically vapor deposited polycrystalline diamond, and gems.
Mesh consists of fine, sand-like diamond crystals ranging in size from submicron to coarse 20 mesh. The crystals occur either as single crystals or in small multiple crystal clusters. Such materials include those marketed by the General Electric Company under the trade names MBS.RTM., MGB.RTM.and RVG.RTM..
Sintered polycrystalline compacts consist of diamond grains that have been sintered into disks by convening diamond powders through the action of a catalyst sweep at diamond-growing conditions. The sintered products contain small amounts of catalyst in pores. The microstructure is dependent on the grain size of the diamond feedstock. It is quasi-isotropic. Sintered products may be leached, leaving porous, catalyst-free material that is thermally stable.
Polycrystalline chemically vapor deposited (CVD) diamonds are dense, metal-free, and substantially non-porous. They are prepared by the energetic decomposition of hydrocarbonaceous species at low pressure. The microstructure is substantially columnar. Textures, flaws and defects are dependent on the processing used to generate the polycrystalline diamond.
Synthetic gems are single crystal products that are coarse, ranging in size from about 0.5 carats to greater than 50 carats. They are dense and generally free of defects. They can only be grown at very slow rates, however, making mass-production time-consuming and expensive.
In the present invention, the novel article can be grown at a relatively quick pace similar to that of CVD diamond, while exhibiting a minimal number of defects resulting in improved thermal, mechanical and optical properties similar to gem diamonds.